diff --git a/ietf/rtp3551.h b/ietf/rtp3551.h
new file mode 100644
index 0000000..ed30193
--- /dev/null
+++ b/ietf/rtp3551.h
@@ -0,0 +1,82 @@
+/*****************************************************************************
+ * rtp3551.h: RTP Profile for Audio and Video
+ *****************************************************************************
+ * Copyright (C) 2013 VideoLAN
+ *
+ * Authors: Benjamin Cohen <bencoh@notk.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject
+ * to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *****************************************************************************/
+
+/*
+ * Normative references:
+ *  - IETF RFC 3551 RTP Profile for Audio and Video Conferences
+ *                  with Minimal Control (July 2003)
+ */
+
+#ifndef __BITSTREAM_IETF_RTP3551_H__
+#define __BITSTREAM_IETF_RTP3551_H__
+
+#include <stdint.h>   /* uint8_t, uint16_t, etc... */
+#include "rtp.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#define RTP_TYPE_GSM         3
+#define RTP_TYPE_L16        10
+#define RTP_TYPE_L16MONO    11
+#define RTP_TYPE_MPA        14
+#define RTP_TYPE_MPV        32
+
+static inline uint32_t rtp_3551_get_clock_rate(uint8_t i_type)
+{
+    /* rtp type is a 7bit positive integer, thus 0xff is invalid */
+    struct {
+        uint8_t i_type;
+        uint32_t i_rate;
+    } profiles[] = {
+        { RTP_TYPE_TS,      90000 },
+        { RTP_TYPE_MPA,     90000 },
+        { RTP_TYPE_MPV,     90000 },
+        { RTP_TYPE_L16,     44100 },
+        { RTP_TYPE_L16MONO, 44100 },
+        { RTP_TYPE_GSM,      8000 },
+
+        { 0xff,             0xffff}
+    };
+
+    int i = 0;
+    while(profiles[i].i_type != 0xff) {
+        if (i_type == profiles[i].i_type) {
+            return profiles[i].i_rate;
+        }
+        i++;
+    }
+    return 0; /* invalid clock rate for unknown type */
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif